915 research outputs found
Exact periodic cross-kink wave solutions for the (2+1)-dimensional Boiti-Leon-Manna-Pempinelli equation
Based on the extended homoclinic test technique and the Hirotaβs bilinear method, the (2+1)-dimensional Boiti-Leon-Manna-Pempinelli equation is investigated which describes the fluid propagating and can be considered as a model for an incompressible fluid. With the aid of symbolic computation, we introduce two new AnsΓ€tz functions to discuss the multiple periodic-soliton solutions of the (2+1)-dimensional Boiti-Leon-Manna-Pempinelli equation. Some entirely new periodic-soliton solutions are presented. The figures corresponding to these solutions are illustrated to show abundant physics structures
from the semileptonic decay and the properties of the meson distribution amplitude
The improved QCD light-cone sum rule (LCSR) provides an effective way to deal
with the heavy-to-light transition form factors (TFFs). Firstly, we adopt the
improved LCSR approach to deal with the TFF up to twist-4
accuracy. Due to the elimination of the most uncertain twist-3 contribution and
the large suppression of the twist-4 contribution, the obtained LCSR shall
provide us a good platform for testing the -meson leading-twist DA. For the
purpose, we suggest a new model for the -meson leading-twist DA
(), whose longitudinal behavior is dominantly determined by a
parameter . Moreover, we find its second Gegenbauer moment .
Varying within certain region, one can conveniently mimic the -meson DA
behavior suggested in the literature. Inversely, by comparing the estimations
with the experimental data on the -meson involved processes, one can get a
possible range for the parameter and a determined behavior for the
-meson DA. Secondly, we discuss the TFF at the maximum recoil
region and present a detailed comparison of it with the pQCD estimation and the
experimental measurements. Thirdly, by applying the LCSR on , we
study the CKM matrix element \Vcb together with its uncertainties by adopting
two types of processes, i.e. the -type and the -type.
It is noted that a smaller shows a better agreement with the
experimental value on \Vcb. For example, for the case of , we obtain
and , whose first (second)
uncertainty comes from the squared average of the mentioned theoretical
(experimental) uncertainties.Comment: 13 pages, 10 figures. Reference updated and discussion improved. To
be published in Nucl.Phys.
Twist-3 light-cone distribution amplitudes of the scalar mesons within the QCD sum rules and their application to the transition form factors
We investigate the twist-3 light-cone distribution amplitudes (LCDAs) of the
scalar mesons , and within the QCD sum rules. The QCD
sum rules are improved by a consistent treatment of the sizable -quark mass
effects within the framework of the background field approach. Adopting the
valence quark component as the dominant structure of the
scalar mesons, our estimation for their masses are close to the measured
, and . From the sum rules, we obtain
the first two non-zero moments of the twist-3 LCDAs :
and ; those of the twist-3 LCDAs
: and ; and those of the twist-3 LCDAs :
and , respectively. As an
application of those twist-3 LCDAs, we study the transition form
factors by introducing proper chiral currents into the correlator, which is
constructed such that the twist-3 LCDAs give dominant contribution and the
twist-2 LCDAs make negligible contribution. Our results of the
transition form factors at the large recoil region are
consistent with those obtained in the literature, which inversely shows the
present twist-3 LCDAs are acceptable.Comment: 14 pages, 12 figures, 7 table
Revisiting the Pion Leading-Twist Distribution Amplitude within the QCD Background Field Theory
We study the pion leading-twist distribution amplitude (DA) within the
framework of SVZ sum rules under the background field theory. To improve the
accuracy of the sum rules, we expand both the quark propagator and the vertex
(z\cdot \tensor{D})^n of the correlator up to dimension-six operators in the
background field theory. The sum rules for the pion DA moments are obtained, in
which all condensates up to dimension-six have been taken into consideration.
Using the sum rules, we obtain \left|_{\rm 1\;GeV} = 0.338 \pm
0.032, \left|_{\rm 1\;GeV} = 0.211 \pm 0.030 and
\left|_{\rm 1\;GeV} = 0.163 \pm 0.030. It is shown that the
dimension-six condensates shall provide sizable contributions to the pion DA
moments. We show that the first Gegenbauer moment of the pion leading-twist DA
is , which is consistent with those
obtained in the literature within errors but prefers a larger central value as
indicated by lattice QCD predictions.Comment: 13 pages, 7 figure
Bisphosphonate- and disumab-related gingival disorders: case analysis from the U.S. Food and Drug Administration Adverse Event Reporting System
Prior research has indicated that bisphosphonates (BPs) can improve periodontal disease because of their anti-osteoporosis properties. In vitro studies have shown that BPs induce cytotoxicity, inhibit wound healing, and thus affect periodontal disease. Denosumab and BPs have alternative indications. BP and denosumab are not known to correlate with gingival disorders. We assessed such a relationship by applying Bayesian and nonproportional analyses to data in the US FDA Adverse Event Reporting System (FAERS) database. The study analyzed BPs and denosumab-reported incidents with preferred terms found in the narrow Standardized MedDRA Queries for gingival disorders. A total of 5863 reported cases of gingival disorders were associated with five BPs (alendronate, pamidronate, ibandronate, risedronate, and zoledronate) and denosumab. More than 15% of patients with gingival disorders related to BPs and denosumab other than denosumab were hospitalized over short- or long-term periods. Our findings indicated BPs and denosumab had significant reporting odds ratios (ROR), proportional reporting ratios (PRR), and information components (IC) with respect to gingival disorders. Pamidronate had the highest association (ROR = 64.58, PRR = 57.99, IC = 5.71), while the weakest association was found with denosumab (ROR = 3.61, PRR = 3.60, IC = 1.77). Significant associations were found between the six drugs and gingival pain, gingival recession, gingivitis, periodontal disease, and periodontitis. In conclusion, our comprehensive overview of the correlations, clinical characteristics, and prognoses of BPs and denosumab-related gingival disorders suggests that these issues deserve continued surveillance and appropriate management
Numerical ability and improvement through interindividual cooperation varied between two cyprinid fish species, qingbo and crucian carp
We used qingbo (Spinibarbus sinensis) and Chinese crucian carp (Carassius auratus) to test whether numerical discrimination could be improved by the coexistence and possible cooperation of conspecies or heterospecies. We conducted a spontaneous shoal choice test of singletons, conspecific dyads and heterospecific dyads under different numerical comparisons (8 vs. 12, 9 vs. 12 and 10 vs. 12). Singletons of qingbo could discriminate only 8 vs. 12, whereas the dyads of qingbo showed better numerical acuity, as they could discriminate 10 vs. 12. Crucian carp may have poor numerical ability, as both singleton and dyads showed no significant preference for larger stimulus shoals, even at the βeasierβ numerical discrimination, that is, 8 vs. 12. Furthermore, heterospecific dyads of crucian carp and qingbo did not show significant preference for larger shoals at any numerical comparison in the present study. It is suggested that both the numerical ability and the possibility for improvement by interindividual interaction and hence cooperation might vary among fish species, and the interaction between heterospecies in the present study showed negative effect on numerical ability possibly due to the different behavioural and cognitive traits which make the information transfer and consensus difficult to reach
ProBDNF Collapses Neurite Outgrowth of Primary Neurons by Activating RhoA
BACKGROUND: Neurons extend their dendrites and axons to build functional neural circuits, which are regulated by both positive and negative signals during development. Brain-derived neurotrophic factor (BDNF) is a positive regulator for neurite outgrowth and neuronal survival but the functions of its precursor (proBDNF) are less characterized. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that proBDNF collapses neurite outgrowth in murine dorsal root ganglion (DRG) neurons and cortical neurons by activating RhoA via the p75 neurotrophin receptor (p75NTR). We demonstrated that the receptor proteins for proBDNF, p75NTR and sortilin, were highly expressed in cultured DRG or cortical neurons. ProBDNF caused a dramatic neurite collapse in a dose-dependent manner and this effect was about 500 fold more potent than myelin-associated glycoprotein. Neutralization of endogenous proBDNF by using antibodies enhanced neurite outgrowth in vitro and in vivo, but this effect was lost in p75NTR(-/-) mice. The neurite outgrowth of cortical neurons from p75NTR deficient (p75NTR(-/-)) mice was insensitive to proBDNF. There was a time-dependent reduction of length and number of filopodia in response to proBDNF which was accompanied with a polarized RhoA activation in growth cones. Moreover, proBDNF treatment of cortical neurons resulted in a time-dependent activation of RhoA but not Cdc42 and the effect was absent in p75NTR(-/-) neurons. Rho kinase (ROCK) and the collapsin response mediator protein-2 (CRMP-2) were also involved in the proBDNF action. CONCLUSIONS: proBDNF has an opposing role in neurite outgrowth to that of mature BDNF. Our observations suggest that proBDNF collapses neurites outgrowth and filopodial growth cones by activating RhoA through the p75NTR signaling pathway
Relativistic Artificial Molecules Realized by Two Coupled Graphene Quantum Dots
Coupled quantum dots (QDs), usually referred to as artificial molecules, are
important not only in exploring fundamental physics of coupled quantum objects,
but also in realizing advanced QD devices. However, previous studies have been
limited to artificial molecules with nonrelativistic fermions. Here, we show
that relativistic artificial molecules can be realized when two circular
graphene QDs are coupled to each other. Using scanning tunneling microscopy
(STM) and spectroscopy (STS), we observe the formation of bonding and
antibonding states of the relativistic artificial molecule and directly
visualize these states of the two coupled graphene QDs. The formation of the
relativistic molecular states strongly alters distributions of massless Dirac
fermions confined in the graphene QDs. Because of the relativistic nature of
the molecular states, our experiment demonstrates that the degeneracy of
different angular-momentum states in the relativistic artificial molecule can
be further lifted by external magnetic fields. Then, both the bonding and
antibonding states are split into two peaks
- β¦